Considering of the complexity of work flow in distribution center, system simulation has become an important tool for its design. Reasonable simulation goal, proper system modeling and correct simulation executing procedure is the precondition for reliable result. Taking a typical DC as an example, which purchases goods from many suppliers, stores them in its warehouse and delivers to their customers according to order, this study developed a simulation model with Flexsim software and then experimented with the model to observe the effect different scenarios may have on the behavior of the model. Based on the simulation statistical report data of model entities, the operation scheme, including the can be optimized with the goal of having the highest profit and the fittest inventory scale. The result illustrate that the highest profit is triple more than the lowest.